Ten Years of the Relative Risk Model and Regional Scale Ecological Risk Assessment

It has been 10 years since the publication of the relative risk model (RRM) for regional scale ecological risk assessment. The approach has since been used successfully for a variety of freshwater, marine, and terrestrial environments in North America, South America, and Australia. During this period the types of stressors have been expanded to include more than contaminants. Invasive species, habitat loss, stream alteration and blockage, temperature, change in land use, and climate have been incorporated into the assessments. Major developments in the RRM have included the extensive use of geographical information systems, uncertainty analysis using Monte Carlo techniques, and its application to retrospective assessments to determine causation. The future uses of the RRM include assessments for forestry and conservation management, an increasing use in invasive species evaluation, and in sustainability. Developments in risk communication, the use of Bayesian approaches, and in uncertainty analyses are on the horizon.

MADS-box基因在水稻和太行花中的相关研究& SAGE 在水稻上应用的生物信息学分析

本论文主要涉及两部分内容：第一部分是水稻和太行花中MADS-box基因的相关研究，第二部分是水稻中SAGE技术的生物信息学分析。 MADS-box基因家族在花发育过程中起着重要的作用。水稻是单子叶植物的模式植物，其基因组序列的公布为在基因组水平上鉴定MADS-box基因提供了条件。根据已发表的水稻MADS-box基因序列，利用关键词搜索、HMMER分析、同源比较、系统进化树分析等手段，对GeneBank和TIGR水稻基因组注释中所有已知和未知的水稻MADS-box基因进行了分析。结果表明，水稻中有64个MADS-box基因编码不同氨基酸，其中已知cDNA序列的为43个。在64个基因中，有23个属于ABCDE类基因，并且其cDNA序列已知，其中的10个已有功能方面的研究。通过3’-RACE和筛选水稻花器官的cDNA文库，得到了一个A类基因片断（A5B2），两个E类基因片断（MW1，MW2）。这三个基因分别与OsMADS14，OsMADS7和OsMADS5相似或相同。禾本科植物花器官的起源，尤其是内外稃的起源仍存在疑问，A功能基因是否以及如何参与其形成成为问题的关键。初步原位杂交分析表明，OsMADS14在花发育的早期开始表达。在小穗原基发育过程中，OsMADS14在内外稃原基中有较强的表达。随着小穗的发育，OsMADS14在整个花序中都有表达。在小穗发育的后期，OsMADS14在胚珠中有较强的表达。OsMADS14的表达模式与FUL类基因一致，并且证明了其在花发育的后期仍然表达强烈，暗示其可能与胚珠发育有重要关系。 SEPALLATA基因被认为是花的特异因子，参与了花的四轮花器官的决定过程。在本文中，通过3’-，5’-RACE，从太行花花芽中克隆了一个MADS-box基因。该基因推导的的氨基酸序列含有典型的M，I，K和C四个结构域，与FBP2和SEP3的相似性较高，系统进化树分析表明该基因属于SEP3亚家族，于是将其命名为TrSEP3。TrSEP3首先在花分生组织中表达，然后在雌雄蕊原基及花瓣中表达;在成熟花中，TrSEP3仅在花瓣和雌蕊中表达。这种表达模式与其它的SEP-like基因有稍不同。TrSEP3拟南芥中过量表达后并未导致表型的改变，暗示其功能与拟南芥的SEP基因可能存在差异。选择压力分析显示TrSEP3受到了不显著的负选择压力。这些结果暗示TrSEP3的功能可能与其它的SEP-like基因有差别，值得进一步研究。 SAGE(Serial Analysis of Gene Expression)是对比样品间转录谱的差异、发现新基因的有效的方法。tag mapping是将SAGE-tag与其转录本匹配的过程，其效率直接影响对转录谱的解释，该过程受多种因素影响。目前，对水稻tag mapping过程缺少详细研究，导致其效率不高。为了确定参考数据库和其它合适的条件，我们利用EST序列和基因组序列构建了不同的参考图谱，从全长cDNA数据库中提取虚拟的SAGE-tag，研究了参考图谱、锚定酶、tag长度以及匹配方法对tag mapping效率的影响，并比较了tag mapping的准确率。结果表明，用EST序列构建的参考图谱能够匹配大多数的SAGE-tag，并具有较高的准确率;利用迭代的方法，可以充分利用基因组序列。各种锚定酶之间的差别不明显，其中NlaIII， HpyCH4V 和 AluI 表现较好;17bp的tag比较适合水稻;而用双锚定酶和17bp的tag则可以显著提高tag mapping的效率和准确率。

The youngest split in sympatric schizothoracine fish (Cyprinidae) is shaped by ecological adaptations in a Tibetan Plateau glacier lake

Although new empirical evidence shows that sympatric speciation has occurred in some species, there are few indisputable model organisms for this process of speciation. The two subspecies (Gymnocypris eckloni eckloni and G. e. scoliostomus) of the schizothoracine Gymnocypris fish species complex from a small glacier lake in the Tibetan Plateau, Lake Sunmcuo, fit several of the key characteristics of the sympatric speciation model. We used combined mitochondrial control region sequences and the cytochrome b gene (1894 bp) to address the phylogenetics and population genetics of 232 specimens of G. e. eckloni and G. e. scoliostomus, as well as all of its closely related sister species. We found that: (i) a total of four old lineages were uncovered in the widespread G. e. eckloni, of which only one was shown to be shared with all G. e. scoliostomus individuals and (ii) the new subspecies (G. e. scoliostomus) evolved in Lake Sunmcuo from the ancestral G. e. eckloni population within approximately 0.057 Ma. These two taxa of the species complex are morphologically distinct, and reproductive isolation is further suggested. Ecological disruptive selection based on morphological traits (e.g. mouth cleft characters) and food utilization may be a mechanism of incipient speciation of two sympatric populations within Lake Sunmcuo. This study provides the first genetic evidence for sympatric speciation in the schizothoracine fish.

Progress in the evaluation of transgenic fish for possible ecological risk and its containment strategies

Genetically improved transgenic fish possess many beneficial economic traits; however, the commercial aquaculture of transgenic fish has not been performed till date. One of the major reasons for this is the possible ecological risk associated with the escape or release of the transgenic fish. Using a growth hormone transgenic fish with rapid growth characteristics as a subject, this paper analyzes the following: the essence of the potential ecological risks posed by transgenic fish; ecological risk in the current situation due to transgenic fish via one-factor phenotypic and fitness analysis, and mathematical model deduction. Then, it expounds new ideas and the latest findings using an artificially simulated ecosystem for the evaluation of the ecological risks posed by transgenic fish. Further, the study comments on the strategies and principles of controlling these ecological risks by using a triplold approach. Based on these results, we propose that ecological risk evaluation and prevention strategies are indispensable important components and should be accompanied with breeding research in order to provide enlightments for transgenic fish breeding, evaluation of the ecological risks posed by transgenic fish, and development of containment strategies against the risks.

A model of dislocations at the interface of the bonded wafers

Wafer bonding is regardless of lattice mismatch in the integration of dissimilar semiconductor materials. This technology differs from the heteroepitaxy mainly in the mechanism of generating dislocations at the interface. A model of dislocations at the bonded interface is proposed in this paper. Edge-like dislocations, which most efficiently relax the strain, are predominant at the bonded interface. But the thermal stress associated with large thermal expansion misfit may drive dislocations away from the bonded interface upon cooling.

a dynamic model to handle defect-oriented processes

Tongji Univ, Inst Dev Study, Syst Engn Soc China, Comm Syst Dynam, Syst Dynam Soc, China Chapter, Shanghai Inst Foreign Trade, Syst Dynam Soc, Chapters Asia Pacific Area